"Humanity on the move": Scientific Advisory Board hands report to German Government

04/25/2016 - More than 2-3 billion people worldwide will move from the country to the cities within the next few decades, doubling the population of the world's slums. It will be the biggest migration of our time. The power of this urbanization surge will be the key driver of global change in the 21st century, reveals the report 'Humanity on the move – Unlocking the transformative power of cities'. It is handed to the German government today by the Advisory Council on Global Change (Wissenschaftlicher Beirat der Bundesregierung Globale Umweltveränderungen, WBGU), co-chaired by Hans Joachim Schellnhuber, director of the Potsdam Institute for Climate Impact Research. Cities are responsible for a disproportionately high percentage of greenhouse-gas emissions – more than two thirds globally. At the same time, they are particularly hard hit by the consequences of global warming. Instead of ever greater densification, therefore, urban development should focus its attention more on the surrounding regions. Developing multiple medium-sized centres instead of a few rampantly expanding megacities increases humankind's resistance to crises and takes the pressure off local resources such as water and land.

Cover of the new report by the German Advisory Council on Global Change (WBGU) for the German Federal Government.

"Urban growth is so immense that it must urgently be channelled in new directions," said WBGU co-chair Dirk Messner, Director of the German Development Institute. If more and more new settlements were to be built with cement and steel in the cities of the developing countries and emerging economies, the energy-intensive production of this building material alone could release such huge quantities of greenhouse gases by 2050 that the world's emissions budget of the 1.5°C target would already be virtually exhausted. Yet there are alternatives, e.g. building with wood or other natural materials. "Without decisive political action and international cooperation, humanity's natural life-support systems would be jeopardized by the demand for resources and the CO2 emissions of urban construction," said Messner.

The living conditions of city dwellers are also an issue here. There are already more than 850 million people today living in inadequate housing conditions. In sub-Saharan Africa, about two thirds of the urban population live in slums, in Asia around a third. Urbanization pressure is especially strong in Asia and Africa, where 90 percent of the global urban population growth is expected to take place. The current refugee movements show how difficult it is even for prosperous countries to cope with a rapid influx of people into their cities. By 2050, the number of people living in inadequate housing could increase by 1 to 2 billion. "This is why the living conditions of people living in extreme poverty in particular must take centre stage in urban development," said Messner. It is this fundamental change of perspective for the new urban agenda that the WBGU aims to initiate at the forthcoming Habitat III conference.

"A city like Hong Kong with its extreme densification is only viable because it sucks in oil, metals and food from the surrounding area and the whole world, digests it, and disposes of residues such as waste, effluent, exhaust gases into the surrounding countryside," explained Schellnhuber. "The distributed nature of renewable-energy generation, the circular economy and even the digital economy makes disaggregation possible – and to some extent even requires it. Polycentric integration in regions such as the German Ruhr area, which is currently re-inventing itself, or the San Francisco Bay Area can be models for the urbanity of the future.